Abstinence has become a primary approach to reducing adolescent pregnancy and STIs, and is a goal of Health People 2010. However, current abstinence research is plagued by inconsistencies and methodological difficulties. This career development proposal will provide the candidate skills to advance our understanding of how relationship and social contexts influence adolescent abstinence decisions using a rigorous theoretical and methodological approach. The ultimate goal is to inform and improve interventions to prevent unintended pregnancy and STIs. The candidate is a pediatrician and adolescent medicine specialist at Indiana University with fellowship training in behavioral research. The training phase has 5 objectives: (1) to advance the theoretical understanding of sexual abstinence as a health behavior, including developmental changes in the individual, interpersonal, and social contexts;(2) to learn theoretical and research design issues in work with adolescent dyads;(3) to develop skills in longitudinal and repeated measures data using advanced analytic techniques;(4) to develop skills necessary for program evaluation and intervention research in adolescent pregnancy and STI prevention;and (5) to advance the candidate's understanding of ethical issues in behavioral research with adolescents. These objectives will be met through formal coursework, directed learning activities, and mentored research. The research plan has three distinct studies. Study 1, a qualitative study, examines abstinence from the adolescent perspective. Study 2, an analysis of abstinence behaviors in the National Survey of Family Growth, seeks to obtain nationally representative estimates. Study 3, a prospective, longitudinal study of the social and relationship contexts of abstinence, will allow an examination of antecedent relationship and contextual issues. Upon completion, the candidate will have the skills and experience to become an independent pediatric scientist poised to advance our understanding of the role of abstinence in pregnancy and STD prevention.